How to Check the Relay Contactor Control Circuit What protection functions does the control circuit

It can only be checked according to the drawings. Among them, the air switch is switched in the protection circuit of the control circuit.

With short circuit, overload protection, contactor.

There is an under-voltage protection thermal relay.

Overload and phase failure protection.

In the power supply system, the most prone faults are short circuit, overload, grounding and lightning strikes, etc. In order to ensure the safe and reliable operation of the power supply system, protection devices must be installed in order to monitor the working conditions of the power supply system, detect faults in time and cut off the power supply of faulty equipment, and prevent the expansion of accidents. The protection circuit is generally composed of various relays, signal indication devices and other components.

It can only be checked according to the drawings.

The air opening has short-circuit and overload protection.

The contactor has undervoltage protection.

Thermal relays are overload and phase-out protected.

Common short-circuit protection and overload protection. Phase sequence protection.

It depends on the specific circuit. Even if the same function is implemented, some are completely unprotected, and some are too complex.

Protecting circuitry can add significantly to the cost and failure rate, so sometimes it can be cumbersome.

The working condition of the relay and contactor is that the coil obtains the rated working voltage, and according to this basic condition, the normally open and normally closed contacts of the relay and contactor are used to arrange and execute according to the requirements of the control logic and non-requirements, so that the coils of the relay and contactor can gain and lose power, so as to control the operation and stop of the equipment.

The contact group mechanism is divided into dynamic group and static group, the static group is fixed, and the dynamic group is composed of insulator and a plurality of contacts and iron cores (sheets). When the solenoid coil is energized, the core in the coil generates a strong magnet, which attracts the core of the dynamic contact group to make the dynamic group contact and the static group contact connected. In this way, the switch is switched on and the corresponding circuit action is controlled.

Summary. Hello, relay protection and automatic action, the impact on the circuit, is to carry out the circuit power-off, the whole circuit to protect the role.

Hello, relay protection and automatic action, the impact on the circuit, is to carry out the circuit power-off, the whole circuit to protect the role.

That's it, isn't there anything more careful?

The main thing is to protect the circuit. Because the role of relay protection is only this one, that is, protection.

At the same time, it can play a role in the detection of the circuit.

Simply connect the relay wire directly to the contactor to be controlled. When the contactor coil is energized, the coil current will produce a magnetic field, and the generated magnetic field will make the static iron core produce electromagnetic attraction to attract the moving core, and drive the AC contactor point to act, the normally closed contact is disconnected, and the normally open contact is closed, and the two are linked. When the coil is de-energized, the electromagnetic attraction disappears, and the armature is released under the action of the release spring, which restores the contact, the normally open contact is disconnected, and the normally closed contact is closed.

The relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control components.

Relays generally have an induction mechanism (input part) that can reflect certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); There is an actuator (output part) that can realize "on" and "off" control of the controlled circuit; Between the input and output parts of the relay, there is also an intermediate mechanism (drive part) that couples and isolates the input quantity, processes the function, and drives the output part.

Relay contactors.

The control system is generally composed of the following two parts:

Relay contactor control diagram.

1.The main circuit of the power supply is often referred to as the primary line circuit.

2.The auxiliary circuit, which is often referred to as the secondary circuit.

The selection of the components of the main circuit and the wires used in the circuit must match the power of the electrical appliances used! Don't do what you want!

For the wire of the auxiliary circuit, you should choose the wire with a square cross-sectional area!

The steps of the method are as follows:

1. When the contact disconnects the inductive load circuit, the energy stored in the load must be consumed by the contact arc In order to eliminate and reduce the harm of the arc when disconnecting the inductive load, prolong the service life of the contact, and eliminate or reduce the electromagnetic interference and damage of the relay to the relevant sensitive circuit, arc suppression protection measures are usually adopted.

2. The output and input of the relay should be avoided as much as possible to be collinear or connected, because when the coil is excited, the back EMF on the coil will be added to the contact, which will increase the disconnection voltage of the contact and interfere with other circuits.

Electrical contacts: There are generally two types of contacts, control contacts and signal contacts. The control contact is powered by 220V 380V voltage, and there is generally a smaller relay or other switch in this circuit, that is to say, when the switch or relay is closed, the coil of the intermediate relay is supplied with power, and the relay is engaged. The signal contact acts as a feedback, which can provide two states, closed and disconnected, so that other control circuits can judge whether the contactor is properly engaged.

The sloped electronic contacts allow the relay to dispense with contact gap adjustment. It can compensate for the contact point caused by the electronic contact.

Relay contacts are the most important component of a relay. Their performance is greatly affected by factors such as the material of the contact, the value of the applied voltage and current (especially the waveform of the voltage and current when the contact is excited and deexcited), the type of load, the operating frequency, the atmospheric environment, the contact configuration and runout. If any of these factors do not meet the predetermined values, problems such as metal electrowinning between contacts, contact welding, wear, or rapid increase in contact resistance can occur.

Generally, you have to choose according to your actual application, whether you can use it or not, because they all have leakage current, you have to see whether the arc of the point is very large, and then choose whether to choose the point protection, what kind of electric shock protection to use, your choice only shows that you use the current of the relay, you have not given the current and impulse current of your load! It is recommended that you can test the steady-state current and inrush current of the ceiling fan motor, and then see if your current relay can be satisfied. Hope it helps!

Contacts and separate resistors Contact and regulator diodes and you have more than one, you have to choose according to the actual needs.

Paste SW temperature measurement adhesive tape to prevent overheating and burning the contacts.

Connect the 220V live wire to the contact terminal of the control board relay, whether to use normally closed contact or normally open contact as needed, and then the other of a pair of contacts is connected to the coil of the AC contactor.

The AC contactor is mainly composed of four parts: (1) electromagnetic system, including suction coil, moving iron core and static iron core; (2) The contact system, including three groups of main contacts and one to two groups of normally open and normally closed auxiliary contacts, which are connected with the moving iron core and linked with each other; (3) Arc extinguishing device, the AC contactor with large capacity is generally equipped with an arc extinguishing device, so as to quickly cut off the arc and avoid burning out the main contact; (4) Insulated shells and accessories, various springs, transmission mechanisms, short-circuit rings, binding posts, etc.

The first question: what you said is completely correct, connect the 220V live wire to the contact terminal of the control board relay, use the normally closed contact or the normally open contact as needed, and then the other of a pair of contacts is connected to the coil of the AC contactor; The second question: the intermediate relay generally refers to a relay used for transition from the control board to the middle of the AC contactor.

The normally open contact of the relay is connected in series with the contactor coil power circuit, and the relay pick-up contactor also picks-up.

Relay (English name: relay) is an electrical control device, which is an electrical appliance that makes a predetermined step change of the controlled quantity in the electrical output circuit when the change of the input quantity (excitation quantity) reaches the specified requirements. It has an interactive relationship between the control system (also known as the input loop) and the controlled system (also known as the output loop).

Usually used in the control circuit of automation, it is actually a kind of "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

The action command is sent to the coil of the relay, and the coil is engaged, driving the normally open or normally closed contact of the relay to change the operating state of the contactor.